The 2008 Chevy Silverado Blowermax

A supercharged, twin-turbocharged, 100-psi, '08 Silverado 2500HD

On first glance, Rod Tschiggfrie's '08 Chevy Silverado 2500 just looks like a mildly modified diesel truck-and that's just the way he wanted it. You see, Rod works as a highway contractor, and it wouldn't do to show up to meetings in some chromed-out show truck with a 20-inch lift. But once you look under the skin of the LMM Chevy, things start to get interesting, and the deeper you go, the wilder they become. If given enough time to explore every nook and cranny of the truck, you'd probably come away with the same feeling we did-that it's one of the most beautiful, labor-intensive, well-engineered vehicles we've ever encountered.

When building the Silverado, Rod wanted to start out with parts that would give him the best possible options when it came to strength, tuning, and ease of use. This led to him extending the 2500's wheelbase by 3 inches and swapping over a complete Ford F-350 front frame and Dana 60 axle (using Dynatrac hubs with an 8-on-6 1/2-inch wheel bolt pattern), which is tied into the factory Chevrolet chassis right under the cab. Before everything was welded together, the frontend was fitted with an Eaton E-Locker (for future sled pulling use), a Dynatrac Free-Spin hub kit, and Race Runner coilover shocks.

Another benefit of the frame and fenderwell extension was that it was easier to work on the elephant in the room-the massive twin-turbocharged, single-supercharged Duramax diesel engine. Assembled by Empire Diesel Performance, the block was bored 0.020 inch and incorporated a 7.1L stroker kit that was sourced from SoCal Diesel. Since the crankshaft would see added stress from the blower drive, it was internally balanced with Mallory heavy metal (stock cranks are externally balanced), which is said to greatly reduce crank flex. An ATI harmonic balancer was also used to keep things vibration-free. Carrillo connecting rods, lower-compression pistons, ported heads, and a camshaft from Empire Diesel Performance round out the engine itself, while modified CP3 pumps and injectors from Exergy Engineering make sure the engine is fed plenty of fuel.

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| This 9.8L supercharger was made by Lysholm of Sweden. For a rough comparison of airflow, that would be about the same as a 130mm turbocharger, which would be impossible to spool on a street truck.

Supercharged And Twin Turbos
The air intake tract is where the truck's Blowermax name comes from, and it's what differentiates Rod's ride from any other. Instead of the factory turbocharger, a pair of large Garrett GT4202 turbochargers feed a mammoth 9.8L screw-type supercharger-a remnant of Rod's offshore boat racing days. With mild tuning, Rod's interesting combination has already yielded 80 psi of boost, which is equally split between the turbochargers and the supercharger. A large air-to-water intercooler underneath the supercharger keeps intake air temperatures just a few degrees warmer than the outside air.

The rest of the truck features the same type of engineering as the engine and is built for strength and durability-not just looks. An ATS Allison transmission with billet shafts and a Co-Pilot takes care of sending the power rearward, while the factory AAM 1150 rear axle has been upgraded with 1 5/8-inch axles and a spool.

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| Although Rod's monster motor hasn't been run on a dyno yet, horsepower is expected to be well into the four-digit range. "I won't stop modifying it until I've hit 2,000 hp," Rod says. And he certainly has the airflow capability to do it!

There are custom pieces everywhere in this truck. From the chromoly traction bars to the Inconel-wrapped, owner-built headers to the tilt front end, every piece on Rod's truck is tweaked, modified, or massaged in some way. Rod's plan after he hits a few truck shows is to start tuning for big power numbers so he can win some dyno contests. After that, it's on to sled pulling and drag racing. While Rod's truck won't be able to compete with purpose-built race vehicles, he may just have the wildest daily driver we've ever seen, and that's fine by us.

Innovative Exhaust
Rod wanted his truck to look and sound impressive, but still be quiet enough for daily use. He didn't want the exhaust to be restrictive, but he wanted a clear path for the exhaust coming out of the 3.0-inch-inducer turbos. His solution was a complicated and impressive one, as there are two complete and separate exhaust systems on the truck. A single 4-inch pipe with an MBRP muffler is used for street cruising, but once the electronically activated, hydraulically raised, 5-inch stacks are turned on, then it's time to race. This way Rod can have his quiet and performance, too-all with just a quick flip of some switches.